Displayer with holograms

ABSTRACT

A displayer for use in a computer comprising a main body, a CRT mounted in the main body and generating an image in an electromagnetic beam, a pair of holograms for projecting the image from the CRT, the holograms mounted in the main body, and a screen for displaying the image projected by the holograms thereon, the screen mounted at a position at which the image is last projected by the holograms. The present invention provides a displayer which provides advantages in that the harmful electromagnetic waves generated from the CRT does not affect the operator by virtue of the holograms, and a screen of a desired large size is obtained at lower cost.

BACKGROUND OF THE INVENTION

The present invention relates to a displayer for use in a computer, and more particularly to a displayer which is provided with holograms for projecting data image generated by a CRT equipped in the main body of the computer and displays the image on a magnifying screen thereof.

Conventionally, display means such as a CRT display is a device for displaying data, outputted from a CPU (central processing unit), on the fluorescent screen thereof by means of electron beam, thereby providing visible data in characters or graphics for the operator. The displayer generally comprises a main body enclosing control units, a keyboard as an input unit and a fluorescent screen for displaying the image thereon in order to allow the operator to see the image.

Known displayer is generally provided with a CRT (Cathode Ray Tube), an EL (Electroluminescence) display device or an LCD (Liquid Crystal Display) device in order to receive data from the CPU and generate a data image which is to be displayed on the screen.

However, the known displayers have disadvantages in that the CRT display provided with the CRT generates harmful electromagnetic waves which affect the operator in case of operation for a long time so that an optical defect and a headache may occur, while the LCD display provided with the LCD, even tough this type of display has no drawback of generation of such electromagnetic waves, causes the manufacturing cost to be considerably higher in proportion to the size of the screen and also a limitation in the size of the screen due to the manufacturing difficulty thereof.

SUMMARY OF THE INVENTION

It is, therefore, an object of the present invention to provide a displayer for use in a computer in which the above disadvantages are overcome and which is provided with reflective holograms, displays data image, generated from a small CRT equipped in the main body thereof, on a magnifying screen by way of the holograms, thereby causing the harmful electromagnetic waves from the CRT not to affect the operator.

It is another object of the present invention to provide a displayer which is capable of magnifying an image from a small-sized CRT by holograms instead of using a large-sized CRT, thus making it possible to reduce the cost of the product.

In one aspect, the above-mentioned objects of the present invention can be accomplished by providing a displayer comprising: a main body, a CRT mounted in said main body and generating an image in an electromagnetic beam, a pair of holograms for projecting said image from said CRT, said holograms mounted in said body, and a screen for displaying said image projected by said holograms thereon, said screen mounted at a position at which said image is last projected by said holograms.

In the above displayer in accordance with this invention, the first hologram is a reflective type hologram manufactured such that a spherical wave W₁ as the reference beam is radiated from a spherical wave scanning point P₁ to the center point of a hologram plate at an angle of incidence θ, a condensed spherical wave W₂ as the object beam is condensed at a beam condensing point P₂ so that an angle of incidence of said condensed spherical wave W₂ to said hologram plate is set as θ, a distance I₁ from said spherical wave scanning point P₁ to said hologram plate is equal to L₁, and also a distance I₂ from said hologram plate to said beam condensing point P₂ is equal to L₂ +L₃,

wherein,

L₁ =a distance from said CRT to said first hologram,

L₂ =a between said first and second holograms,

L₃ =a distance from said second hologram to an image first product by said first hologram.

Also, the second hologram is a reflective type hologram manufactured such that a condensed spherical wave W₃ as the reference beam is condensed at a beam condensing point P₃ so that an angle of incidence of said condensed spherical wave W₃ to a hologram plate is set as θ, a condensed spherical wave W₄ as the object beam is condensed at a beam condensing point P₄ so that an angle of incidence of said condensed spherical wave W₄ to said hologram plate is set as θ, and a distance 1₃ from said beam condensing point P₃ to said hologram plate is equal to L₃, and also a distance I₄ from said hologram plate to said beam condensing point P₄ is equal to L₄.

wherein,

L₃ =a distance from said second hologram to an image first produced by said first hologram.

L₄ =a distance from said second hologram to an image second produced by said second hologram.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a schematic view representing the construction of a displayer provided with holograms in accordance with the present invention;

FIG. 2 is a view representing the image projection by the holograms, a first hologram and a second hologram of the displayer of FIG. 1;

FIG. 3 is a view illustrating the principle for manufacturing the first hologram of FIG. 2; and

FIG. 4 is a view illustrating the principle for manufacturing the second hologram of FIG. 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to FIG. 1 with a schematic view representing the construction of a displayer provided with holograms in accordance with the present invention, the displayer comprises a small cathode ray tube 2 (hereinafter, referred to simply as "the CRT") mounted in the rear inside portion of a main body 1 of a computer, a first hologram 3 arranged inside the main body 1 before the CRT 2 at an inclination angle in order to first project the image having generated from the CRT 2, a second hologram 6 arranged over the first hologram 3 in order to face therewith in parallelism and be spaced therefrom and adapted to second project the image having first projected by the first hologram 3 and display the image on a magnifying screen 5. Also, the displayer further comprises a casing 7 for shielding the inside thereof from the outside light and protecting the enclosures from the outside shock, and a keyboard 8 as an input unit.

Here, the above-mentioned elements of the displayer are arranged such that the distance from the CRT 2 to the first hologram 3 is a distance L₁, the distance between the first and second holograms 3 and 6 is a distance L₂ and the distance form the second hologram 6 to the enlarging screen 5 is a distance L₄, as shown in FIG. 2.

Turning next to FIG. 3 which is a view illustrating the principle for manufacturing the first hologram 3, the first hologram 3 is a reflective hologram manufactured such that a spherical wave W₁ as the reference beam is radiated from the spherical wave scanning point P₁ to the center point of a hologram plate 3' at an angle of incidence θ, and a condensed spherical wave W₂ as the object beam is condensed at a beam condensing point P₂ so that an angle of incidence of the W₂ to the hologram plate 3' is set as θ, and a distance I₁ from the scanning point P₁ to the hologram plate 3' is equal to the distance L₁, and also the distance I₂ from the hologram plate 3' to the condensing point P₂ is equal to a sum total of the distances L₂ and L₃, that is L₂ +L₃ as shown in FIG. 2.

FIG. 4 is a view illustrating the principle for manufacturing the second hologram 6. As shown in the drawing, the second hologram 6 is a reflective hologram manufactured such that a condensed spherical wave W₃ as the reference beam is condensed at a beam condensing point P₃ so that an angle of incidence of the condensed spherical wave W₃ to a hologram plate 6' is set as θ, a condensed spherical wave W₄ as the object beam is condensed at a beam condensing point P₄ so that an angle of incidence of the condensed spherical wave W₄ to the hologram plate 6' is set as θ, and a distance I₃ from the condensing point P₃ to the hologram plate 6' is equal to the distance L₃ of FIG. 2, and also the distance I₄ from the hologram 6' to the condensing point P₄ is equal to the distance L₄ as shown in FIG. 2.

Here, the first and second holograms 3 and 6 are, as shown in FIG. 2, so arranged that they are inclined to the horizontal line at the angle of inclination θ. Also, the range of the angle of inclination θ is such that at its minimum, the vertical axis of the first hologram 3 does not cross the uppermost point A of the CRT 2 as shown in FIGS. 1 and 2, and the maximum value thereof does not exceed 45°.

Turning again to FIG. 2, the image 4 at the CRT 2 is accordingly first produced by said first hologram 3 in order to be a first produced image 4a produced at a position in a distance L₂ +L₃ from the center portion of the first hologram 3.

The CRT 2 generates the image 4 displaying data outputted from the CPU and radiates an electromagnetic beam of the image 4 to the first hologram 3 arranged as inclined to the optical path of the CRT 2 at the angle of inclination θ so that a distortion occurs in the first produced image 4a.

Thereafter, the first projected image 4a is second projected by means of the second hologram 6 in order to be a second projected image 4b, said image 4b projected on the magnifying screen 5. At this time, the second hologram 6 is located in order to face with the first hologram 3 in parallelism as described above. Therefore, the first image 4a is inclined to the optical path of the second hologram 6 at the angle of inclination θ so that the distortion of the first projected image 4a is compensated.

In accordance with the above manufactured method for the holograms, data outputted from the CPU is converted into the image by means of the small CRT 2 and last projected on the magnifying screen 5 by way of the holograms 3 and 6.

At this time, the magnification "m" of the image projected on the screen 5 is given by the following relationship: ##EQU1##

Therefore, the magnitude "Sm" of the image 4b projected on the screen 5 is equal to the value of the magnitude "Cm" of the image 4 at the CRT 2 multiplied by the magnification "m", that is Sm=Cm×m.

In the above relationship, expression 1 denotes the magnification "m₁ " by the first hologram 3 and expression 2 denotes the magnification "m₂ " by the second hologram 6. Also, the magnification "m₁ " has to be equal to the magnification m₂ in order to efficiently compensate the distortion of the projected image.

For example, a 14" displayer provided with a 5" CRT can be designed only by calculating the distance L₁ from the CRT to the first hologram 3 and the distance L₄ from the second hologram 6 to the screen 5 depending on the desired size of the CRT display.

In other words, the magnification "m" of the above displayer for magnifying 5" magnitude into 14" magnitude is 2.8, also the magnifications m₁ and m₂ are equal to each other as described above. Therefore, the magnifications m₁ and m₂ will be calculated by √m, that is √2.8≃1.67. Also, if the distances L₁ and L₄ are set as 200 mm and 300 mm, respectively, the distance L₃ from the second hologram 6 to the first projected image 4a will be calculated by the following expression:

    m.sub.2 =L.sub.4 /L.sub.3, therefore L.sub.3 =L.sub.4 /m.sub.2

In accordance, the distance L₃ =300 mm/1.67≃179.6 mm.

In the same manner, the distance L₂ from the first hologram 3 to the second hologram 6 is calculated by the following expression:

    m.sub.1 =(L.sub.2 +L.sub.3)/L.sub.1

Therefore, the distance L₂ =(m₁× L₁)-L₃ =(1.67×200)-179.6=154.4 mm.

Accordingly, if the distances L₁ and L₄ of the 14" displayer provided with the 5" CRT are set as 200 mm and 300 mm, respectively, another distances L₃ and L₂ of the displayer are set as about 179.6 mm and about 154.4 mm, respectively.

Also, the harmful electromagnetic waves generated from the CRT 2 are prevented from affecting the operator by means of the holograms 3 and 6, thereby protecting the operator from the harmful electromagnetic waves.

As described above, the present invention provides the displayer which is provided with a small CRT and holograms therein in order to project the image from the CRT on the magnifying screen by virtue of the reflection of the holograms so that it has advantages in that the harmful electromagnetic waves generated from the CRT does not affect the operator by virtue of the holograms, and a screen of a desired large size is obtained at lower cost.

Although the preferred embodiments of the present invention have been disclosed for illustrative purpose, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. 

What is claimed is:
 1. A displayer with holograms comprising:a CRT disposed in a computer main body for generating an image; a pair of holograms for projecting said image to a screen; and a screen for displaying thereon said image projected by said holograms; said holograms comprising a pair of holograms, a first hologram arranged inclined to a horizontal line associated with said CRT in order to first project said image from said CRT, and a second hologram arranged facing said first hologram and spaced apart therefrom in order to further project said image, which was first projected by said first hologram, on said screen and to compensate distortions of said image which was first projected; wherein said first hologram is a reflective type hologram manufactured such that a spherical wave W₁ as a reference beam is radiated from a spherical wave scanning point P₁ to the center point of a hologram plate at an angle of incidence θ, a condensed spherical wave W₂ as an object beam is condensed at a beam condensing point P₂ so that an angle of incidence of said condensed spherical wave W₂ to said hologram plate is set as θ, a distance l₁ from said spherical wave scanning point P₁ to said hologram plate is equal to L₁, and also a distance l₂ from said hologram plate to said beam condensing point P₂ is equal to L₂ +L₃ ; wherein, L₁ =a distance from said CRT to said first hologram, L₂ =a distance between said first and second holograms, L₃ =a distance from said second hologram to an image first produced by said first hologram.
 2. A displayer according to claim 1, wherein said angle of incidence θ is greater than an angle defined by the intersection of an upper edge of said CRT and an axis of the CRT and is less than 45°.
 3. A displayer with holograms comprising:a CRT disposed in a computer main body for generating an image; a pair of holograms for projecting said image to a screen; and a screen for displaying thereon said image projected by said holograms; said holograms comprising a pair of holograms, a first hologram arranged inclined to a horizontal line associated with said CRT in order to first project said image from said CRT, and a second hologram arranged facing said first hologram and spaced apart therefrom in order to further project said image, which was first projected by said first hologram, on said screen and to compensate distortions of said image which was first projected; wherein said second hologram is a reflective type hologram manufactured such that a condensed spherical wave W₃ as the reference beam is condensed at a beam condensing point P₃ so that an angle of incidence of said condensed spherical wave W₃ to a hologram plate is set as θ, a condensed spherical wave W₄ as the object beam is condensed at a beam condensing point P₄ so that an angle of incidence of said condensed spherical wave W₄ to said hologram plate is set as θ, and a distance l₃ from said beam condensing point P₃ to said hologram plate is equal to L₃, and also a distance l₄ from said hologram plate to said beam condensing point P₄ is equal to L₄ ; wherein, L₃ =a distance from said second hologram to an image first projected by said first hologram; and L₄ =a distance from said second hologram to an image second projected by said second hologram.
 4. A displayer with holograms comprising:a CRT disposed in a computer main body for generating an image; a pair of holograms for projecting said image to a screen; and a screen for displaying thereon said image projected by said holograms; said holograms comprising a pair of holograms, a first hologram arranged inclined to a horizontal line associated with said CRT in order to first project said image from said CRT, and a second hologram arranged facing said first hologram and spaced apart therefrom in order to further project said image, which was first projected by said first hologram, on said screen and to compensate distortions of said image which was first projected; wherein said displayer has a magnification "m" of said image projected on said screen with respect to said image generated by said CRT which is given by the following relationships: ##EQU2## m₁ =m₂ wherein,m₁ =a magnification by said first hologram, and m₂ =a magnification by said second hologram, 